Bruxism is a common dental problem which when undiagnosed or poorly managed for a long period of time can cause very significant cosmetic and functional dental problems and lead to great expense on dental treatment. In fact, bruxism is one of the greatest risks to the longevity of teeth and almost all types of dental treatment. It has been found that veneers fail seven times faster and crowns fail two to three times faster in the mouth of a bruxer compared to normal patients. Dental implants are almost twice as likely to have complications in tooth grinders. Aside from expensive treatments, fractures of parts of teeth are a very common cause of fillings and root canal treatments, on which many tens of billions are being spent each year. Many of these treatments are paid for by insurance companies and would be avoidable if bruxism were better managed.
Splints are highly effective at preventing tooth wear/fractures and facial pain—so long as they are used. Many types of splints exist, and these can be fabricated from hard or soft polymer or a combination of multi-layered, polymer-based mouth guard materials. One type of known splint is a hard/soft splint. Conventional hard/soft splint designs have a soft layer comprising a top surface, a bottom surface and two side surfaces. The bottom surface of the soft layer is adapted to be in contact with the teeth the splint is fitted on, while the top surface of the soft layer is coupled to a hard outer layer. The hard outer layer is adapted to be in contact with the opposing teeth and protects against the high force effects of bruxism. The two side surfaces of the soft layer are thus left exposed when positioned in the mouth of a user. In current use, these splints are usually made by a thermoforming process. A bilayered hard and soft sheet or foil is heated to a temperature where it can easily be adapted by pressure or a vacuum around a stone model of the mouth. Once adaption is complete, the excess foil is trimmed and shaped into an acceptable splint shape and delivered to the patient. Another type of splint is a hard splint. A hard splint can be fabricated using many techniques. One typical fabrication technique is through the use of heat-processed PMMA, with the splint cast in a lost wax process. Another fabrication technique is where the hard splint is built up directly on a model using PMMA monomer and polymer powder, known as the “salt and pepper” technique. A further type of hard splint is made by adapting light cured material, in unpolymerised form, either directly to the teeth intra-orally, or to a model of the teeth, and then light curing the material.
There are a number of problems associated with existing splints. Firstly, they tend to be bulky, and as a result about 50% of patients stop using them after 12 months, even though many dentists recommend that they be used for life. Most patients will continue to grind their after ceasing splint use. As a result, many patients presenting with severe bruxism-related problems report having tried a splint for a short time but gave up using it. While bruxism persists over many years in most patients, for some it is a temporary problem, possibly related to a stressful time of life. For these cases, lifelong splint use is not required, yet many dentists will recommend replacing splints every 2 to 3 years, and thus burdening patients with the associated expense involved in buying a replacement splint.
Accordingly, there are a number of issues encountered by dentists with treating bruxism. In particular, it can be difficult to establish when to prescribe splints, how to monitor splint effectiveness and patient compliance with the use of the splint, as well as when it should be recommended that splint use be discontinued. Therefore, because of the lack of a means of objectively monitoring bruxism over time, many patients who need splints are not using them and many patients who do not need splints are wasting money on them.
There have been a number of devices which have been developed in an attempt to address these issues. Some of these devices have been designed to detect bruxism in a patient. One such known device is based on an experimental method (EMG) of monitoring activity in the muscles involved in chewing. It comes as a single use adhesive pad, which attaches to the side of the face and measures the presence/absence and the severity of bruxism over the course of 24 hours. However, this device only lasts for 24 hours and is relatively expensive to buy. If the patient doesn't grind on the night of use (which is at least 25% likely), then false negatives are unavoidable. It also can take at 2 weeks to establish a meaningful pattern. Furthermore, it has been found that the EMG monitoring of bruxism is very heavily contaminated with artefacts, making reliable automated bruxism diagnosis very difficult.
Other known devices have been developed to reduce bruxism intensity. One such device consists of an electrode that detects activity in the chewing muscles during bruxism. Once activity in these muscles exceeds a certain threshold, the device delivers a small electric shock to the muscle which is intended to reduce bruxism intensity. However, it is uncertain that the effects on bruxism activity are sustained in the long-term, and the device is very cumbersome to use during sleep. Also, there are broader health concerns about this approach related to disturbance of sleep. In addition, a splint is still recommended, as the shock therapy only reduces the bruxism activity.
Other devices have been developed to determine whether a splint is being used by a patient. One known such device integrates into a splint, and uses temperature monitoring to determine whether the splint is being used by a patient. However, it does not monitor actual bruxism activity in any way. Therefore it has no diagnostic capability whatsoever and only monitors compliance, without the capacity to reinforce it with personalised feedback on the severity of the condition. It also offers no direct evidence to patients that they are still grinding and therefore no reason to believe that splint use is still needed.
Another known device measures how a splint flexes under biting. It comprises a sensor strip which is easily integrated with the outer surface of a splint, rather than inside the normal splint contour. As a result, this device is very bulky. In addition, it cannot be used in the cheaper “boil and bite” splints or in the hard-soft type splints. It also typically lasts for only 6 months and cannot be recharged. A further drawback of this device is that a patient has to visit the dentist to have the data downloaded. As a result, no on-going compliance reinforcement can happen. In addition, the device must be used with a base station, which must be worn around the neck or in a pocket at night.
There are also some patent applications which have attempted to address many of the problems mentioned above. These include International Patent Publication Nos. WO 2010/023655, WO 2000/44284, WO 2006/068896 and WO 2011/091355, as well as U.S. Pat. No. 5,078,153 and US Patent No. 20133/211270 and German Patent Application No. DE 102004043665.
It will be appreciated therefore that all of the devices developed to date in an attempt to address the issues related to bruxism detection and monitoring suffer from different drawbacks. As a result, there is currently no accurate, easy to use and long lasting device that successfully overcomes all of the above mentioned issues.